Journal of Energy Bioscience 2025, Vol.16, No.3, 117-127 http://bioscipublisher.com/index.php/jeb 125 9.3 Research gaps: scalability, microbial tolerance, policy models. Although the effect of sorghum in making ethanol is quite good in laboratories and small trials, there are still many problems in large-scale application. First, the economic benefits and technical details of large-scale production need to be resolved. For example, the price of enzymes, the energy used in pretreatment, and whether by-products can be used, all need further research (van Rijn et al., 2018; Boboescu et al., 2019). Second, the high sugar and inhibitory environment is a challenge for fermentation bacteria. If you want to increase yields, you have to find strains that are more tolerant to these environments, or modify them (Sathesh-Prabu and Murugesan, 2011; van Rijn et al., 2018). Another big problem is the policy level. For example, how to use land, how to ensure food security, and how to balance energy and agricultural development, all of these lack systematic research. Only by considering these socioeconomic issues together can we truly promote the sustainable development of sorghum ethanol (Prasad et al., 2007; van Rijn et al., 2018; Batog et al., 2020). 10 Conclusions Sorghum biomass has high yield, strong drought resistance, and adaptability to different environments. It is a very promising fuel ethanol feedstock. If the pretreatment method is optimized, such as using organic solvents, alkali or enzymes, the yield of sugar and ethanol can be greatly increased. Different sorghum varieties and their planting methods (such as as main crops, double crops or planting in marginal land) will affect ethanol production. Some varieties can also have good yields when planted in temperate and marginal plots. Technical and economic analysis shows that if the by-products can be fully utilized, small ethanol plants using sweet sorghum are promising to make money. Planting sorghum straw and marginal land can also reduce competition with food crops and make the whole more sustainable. From a technical and economic point of view, it is reliable to use sorghum for fuel ethanol. As long as the variety is selected and combined with reasonable processing and fermentation technology, the ethanol yield can even be similar to that of sugarcane. In the main crop or double cropping mode, some varieties (such as Sucrosorgo 506, BRS 506, GN-4) can have high yields in temperate and tropical regions. Economic analysis also found that if the whole sorghum plant and its byproducts are used, the payback time is fast and the rate of return is high. In addition, the use of marginal land and waste can also improve environmental and social sustainability. However, the yield and economic benefits of marginal land are still not as good as those of good land. In this regard, more suitable varieties need to be selected and the technology needs to be improved. Suggestions for different participants: For researchers: Continue to improve sorghum varieties, increase sugar content and total yield, reduce lignin, and make sugar easier to extract. Study more energy-saving, cost-saving and efficient processing and fermentation methods. Conduct more field trials to test the performance of different regions and varieties and find the most stable combination. For policymakers: Introduce policies to encourage the planting of non-grain energy crops such as sorghum, especially to support multiple cropping and the use of marginal land. Promote the development and utilization of byproducts and the construction of the entire industrial chain. It is also necessary to increase financial support to reduce the risk of initial investment by enterprises. For enterprises: Consider investing in sorghum ethanol projects, give priority to high-yield and adaptable varieties, and adopt efficient pretreatment technologies. By-products should not be wasted. For example, they can be used as pellet fuel, feed or food to further increase profits. At the same time, we should cooperate with farmers and scientific research institutions to establish a stable supply chain of raw materials and technologies. For farmers: Choose sorghum varieties suitable for local climate and soil, and reasonably arrange main crops and repeated crops to make land use more efficient. Participating in the sorghum supply chain can not only sell grain, but also earn more income through straw and by-products. Pay more attention to the promotion of new technologies and new varieties, which can increase production and be more resistant to risks.
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